As the number of agents and treatment regimens for cancer has increased, clinicians and researchers are seeking to fully elucidate the biological, chemical, pharmacological, and cellular mechanisms which are responsible for the pathogenesis and pathophysiology of the various adverse disease manifestations, as well as how chemotherapeutic drugs exert their anti-cancer and cytotoxic or cytostatic activity on a biochemical and pharmacological basis. As described herein, with the exception of the novel conception and practice of the present invention, there are no currently-approved compositions which markedly increase the survival time of a cancer patient via a targeted therapeutic interaction that involves the direct modulation of either the thioredoxin or glutaredoxin pathways, thereby leading to increased anti-cancer and cytotoxic effects of the chemotherapeutic agent(s) within the cancer cells. Moreover, prior to the clinical studies described in the present invention, no clinical studies utilizing the novel treatment methods and compositions disclosed herein have observed “an increase in patient survival time” in a medically-important manner, but rather measured only “patient response” (i.e., tumor response—a shrinkage of tumor that is observed radiographically). These are highly innovative and novel features of the present invention.
It has been increasingly recognized that many different types of cancer cells have been shown to have increased expression and/or activity of thioredoxin and/or glutaredoxin including, but not limited to, lung cancer, colorectal cancer, gastric cancer, esophageal cancer, ovarian cancer, cancer of the biliary tract, gallbladder cancer, cervical cancer, breast cancer, endometrial cancer, vaginal cancer, prostate cancer, uterine cancer, hepatic cancer, pancreatic cancer, and adenocarcinoma.
Thioredoxin and glutaredoxin are members of the thioredoxin superfamily; that mediate disulfide exchange via their Cys-containing catalytic sites. While glutaredoxins mostly reduce mixed disulfides containing glutathione, thioredoxins are involved in the maintenance of protein sulfhydryls in their reduced state via disulfide bond reduction. See, e.g., Print, W. A., et al., The role of the thioredoxin and glutaredoxin pathways in reducing protein disulfide bonds in the Escherichia coli cytoplasm. J. Biol. Chem. 272:15661-15667 (1996). The reduced form of thioredoxin is generated by the action of thioredoxin reductase; whereas glutathione provides directly the reducing potential for regeneration of the reduced form of glutaredoxin. Glutaredoxins are oxidized by substrates, and reduced non-enzymatically by glutathione. In contrast to thioredoxins, which are reduced by thioredoxin reductase, no oxidoreductase or substrate, other than those described in the present invention, has been reported to specifically reduce glutaredoxins. Instead, oxidized glutathione is regenerated by glutathione reductase. Together these components comprise the glutathione system. See, e.g., Holmgren, A. and Fernandes, A. P., Glutaredoxins: glutathione-dependent redox enzymes with functions far beyond a simple thioredoxin backup system. Antioxid. Redox. Signal. 6:63-74 (2004); Holmgren, A., Thioredoxin and glutaredoxin systems. J. Biol. Chem. 264:13963-13966 (1989). The thioredoxin system, together with the glutathione system, is regarded as a main regulator of oxidative metabolism involving the intracellular redox environment, exercising control of the cellular redox state and antioxidant defense, as well as governing the redox regulation of several cellular processes. The system is involved in direct regulation of: (i) several transcription factors, (ii) apoptosis (i.e., programmed cell death) induction, and (iii) many metabolic pathways (e.g., DNA synthesis, glucose metabolism, selenium metabolism, and vitamin C recycling). See, e.g., Amér, E. S. J., et al., Physiological functions of thioredoxin and thioredoxin reductase. Eur. J. Biochem. 267:6102-6109 (2000).
In brief, the overexpression (or increased activity, or both) of thioredoxin or glutaredoxin in cancer cells mediates a multi-component and multi-pathway mechanism which confers a survival advantage to cancer cells. Overexpression/increased levels or responsiveness mediated by thioredoxin and/or glutaredoxin in cancer cells can lead to several important biological alterations including, but not limited to: (i) loss of apoptotic sensitivity to therapy (i.e., drug or ionizing radiation resistance); (ii) increased conversion of RNA into DNA (involving ribonucleotide reductase); (iii) altered gene expression; (iv) increased cellular proliferation signals and rates; (v) increased thioredoxin peroxidase; and (vi) increased angiogenic activity (i.e., increased blood supply to the tumor). Accordingly, by pharmacological inactivation or modulation of thioredoxin and/or glutaredoxin by the proper medical administration of effective levels and schedules of the compositions of the present invention, can result in enhancement of chemotherapy effects and thereby lead to increased patient survival.
The compositions of the present invention comprise a medically-sufficient dose of an oxidative metabolism-affecting Formula (I) compound. The compounds of Formula (I) include pharmaceutically-acceptable salts of such compounds, as well as prodrugs, analogs, conjugates, hydrates, solvates and polymorphs, as well as stereoisomers (including diastereoisomers and enantiomers) and tautomers of such compounds. The Formula (I) compounds of the present invention also comprise a medically-sufficient dose of the disodium salt of 2,2′-dithio-bis-ethane sulfonate, which has been referred to in the literature as Tavocept™, dimesna, and BNP7787. The compositions of the present invention also comprise a medically-sufficient dose of the metabolite of disodium 2,2′-dithio-bis-ethane sulfonate, known as 2-mercapto ethane sulfonate sodium (also known in the literature as mesna) and 2-mercapto ethane sulfonate as a disulfide form which is conjugated with a substituent group consisting of: -Cys, -Homocysteine, -Cys-Gly, -Cys-Glu, -Cys-Glu-Gly, -Cys-Homocysteine, -Homocysteine-Gly, -Homocysteine-Glu, -Homocysteine-Glu-Gly, and
wherein R1 and R2 are any L- or D-amino acid.
The underlying mechanisms of the Formula (I) compounds of the present invention in increasing the survival time of cancer patients involves one or more of several novel pharmacological and physiological factors, including but not limited to, a prevention, compromise and/or reduction in the levels, responsiveness, or in the concentration and/or tumor protective metabolism of various physiological cellular thiols; these antioxidants and enzymes are increased in concentration and/or activity in cancer cells, respectively, due in part to activation and/or overexpression of thioredoxin and/or glutaredoxin levels or activity which are present in many cancer cells, and this increase in concentration and/or activity may be may be further enhanced by exposure to cytotoxic chemotherapeutic agents in tumor cells. The Formula (I) compounds of the present invention may exert therapeutic medicinal and pharmacological activity by the intrinsic composition of the molecule itself (i.e., an oxidized disulfide), as well as by oxidizing free thiols to form oxidized disulfides (i.e., by non-enzymatic SN2-mediated reactions, wherein attack of a thiol/thiolate upon a disulfide leads to the scission of the former disulfide which is accompanied by the facile departure of a thiol-containing group). As the thiolate group is far more nucleophilic than the corresponding thiol, the attack is believed to be via the thiolate, however, in some cases the sulfur atom contained within an attacking free sulfhydryl group may be the nucleophile), and may thereby lead to pharmacological depletion and metabolism of reductive physiological free thiols (e.g., glutathione, cysteine, and homocysteine).
Overexpression/increased levels or increased responsiveness mediated by thioredoxin and/or glutaredoxin in cancer cells leads to loss of apoptotic sensitivity to therapy (i.e., drug or ionizing radiation resistance), increased conversion of RNA into DNA (involving ribonucleotide reductase), increased gene expression, increased thioredoxin peroxidase, and increased angiogenic activity (i.e., increased blood supply to the tumor). Accordingly, pharmacological inactivation or modulation of thioredoxin and/or glutaredoxin by the proper medical administration of effective levels and schedules of the compositions of the present invention can result in increased patient survival.
It is believed by the Applicant of the present invention that these aforementioned mechanisms of action are mediated by the Formula (I) compounds of the present invention and metabolites thereof (e.g., 2-mercapto ethane sulfonate (mesna) and mesna heteroconjugates) and are directly involved in the marked increase in the survival time of patients suffering from cancer including, but not limited to, non-small cell lung carcinoma (NSCLC) or adenocarcinoma who received treatments utilizing the compositions, formulation, and methods of the present invention. This has extremely important implications for advancing the treatment of patients with cancer.
Compositions and formulations comprising the Formula (I) compounds of the present invention may be given using any combination of the following three general treatment methods: (i) in a direct inhibitory or inactivating manner (i.e., direct chemical interactions that inactivate thioredoxin and/or glutaredoxin) and/or depletive manner (i.e., decreasing thioredoxin and/or glutaredoxin concentrations or production rates), thereby increasing the susceptibility of the cancer cells to any subsequent administration of any chemotherapeutic agent or agents that may act directly or indirectly through the thioredoxin- and/or glutaredoxin-mediated pathways in order to sensitize the patient's cancer and thus increase the survival of the patient; and/or (ii) in a synergistic manner, where the anti-thioredoxin and/or glutaredoxin therapy is concurrently administered with chemotherapy administration when a cancer patient begins any chemotherapy cycle, in order to increase and optimize the pharmacological activity directed against thioredoxin- and/or glutaredoxin-mediated mechanisms present while chemotherapy is being concurrently administered; and/or (iii) in a post-treatment manner (i.e., after the completion of chemotherapy dose administration or a chemotherapy cycle) in order to maintain the presence of a pharmacologically-induced depletion, inactivation, or modulation of thioredoxin and/or glutaredoxin in the patient's cancer cells for as long as optimally required. Additionally, the aforementioned compositions and formulations may be given in an identical manner to increase patient survival time in a patient receiving treatment with a cytotoxic or cytostatic anti-cancer agent by any additionally clinically-beneficial mechanism(s).
I. Oxidative Metabolism
In its most simple terms, oxidative metabolism refers to the enzymatic pathways leading to the addition of oxygen (i.e., oxidation) or the removal of electrons or hydrogen (i.e., reduction) from intermediates in the pathways. The redox state of any particular biological environment can be defined as the sum of oxidative and reductive processes occurring within that environment which, in turn, directly relates to the extent to which molecules are oxidized or reduced within it. The redox potential of biological ions or molecules is a measure of their tendency to lose an electron (i.e., thereby becoming oxidized) and is expressed as E0 in volts. The more strongly reducing an ion or molecule, the more negative its E0. As previously stated, under normal physiological circumstances, most intracellular biological systems are predominantly found in a reduced state. Within cells, thiols (R—SH) such as glutathione (GSH), cysteine, homocysteine, and the like, are maintained in their reduced state, as are the nicotinamide nucleotide coenzymes NADH and NADPH. The opposite relationship is found in plasma, where the high partial pressure of oxygen (pO2) promotes an oxidative environment, thereby leading to a high proportion (i.e., greater than 90%) of the physiological sulfur-containing amino acids and peptides (e.g., glutathione (GSH)) existing in stable oxidized (disulfide) forms. In plasma, there are currently no known enzymes that appear to reduce the disulfide forms of these sulfur-containing amino acids and GSH; this further contributes to the plasma vs. cellular disparity in terms of the relative proportions of physiological disulfides vs. thiols. Physiological circumstances can, however, arise which alter the overall redox balance and lead to a more oxidizing environment in the cell. Various complex physiological systems have evolved to remove, repair, and control the normal reducing environment. However, when the oxidizing environment overwhelms these protective mechanisms, oxidative damage and profound biological and toxic activity can occur.
In biological systems, the formation of potentially physiologically-deleterious reactive oxygen species (ROS) and that of reactive nitrogen species (RNS), may be caused from a variety of metabolic and/or environmental processes. By way of non-limiting example, intracellular ROS (e.g., hydrogen peroxide: H2O2; superoxide anion: O2−; hydroxyl radical: OH−; nitric oxide: NO; and the like) may be generated by several mechanisms: (i) by the activity of radiation, both exciting (e.g., UV-rays) and ionizing (e.g., X-rays); (ii) during xenobiotic and drug metabolism; and (iii) under relative hypoxic, ischemic and catabolic metabolic conditions, as well as by exposure to hyperbaric oxygen. Protection against the harmful physiological activity of ROS and RNS species is mediated by a complex network of overlapping mechanisms and metabolic pathways that utilize a combination of small redox-active molecules and enzymes coupled with the expenditure of reducing equivalents. These complex networks of mechanisms, metabolic pathways, small redox-active molecules, and enzymes will be fully discussed, infra.
Concentrations of ROS and RNS which cannot be adequately dealt with by the endogenous antioxidant system can lead to damage of lipids, proteins, carbohydrates, and nucleic acids. Changes in oxidative metabolism which lead to an increase in the oxidizing environment and the formation of potentially physiologically-deleterious reactive oxygen species (ROS) and that of reactive nitrogen species (RNS) has been generally termed within the literature as “oxidative stress”. It has also recently been recognized that cancer cells may respond to such “oxidative stress”, induced by chemotherapy or radiation exposure, by decreasing the concentrations of ROS and oxidized thiols and well as by increased concentrations of thiol and anti-oxidants. It should be noted that when either or both of these mechanisms are operative, the subject's tumor cells may become resistant to chemotherapy and radiation therapy, thereby representing an important obstacle to curing or controlling the progression of the subject's cancer.
The putative mechanisms of the Formula (I) compositions of the present invention which function in the potentiation of the anti-cancer activity of chemotherapeutic agents may involve one or more of several novel pharmacological and physiological factors, including but not limited to, a prevention, compromise, and/or reduction in the normal increase, responsiveness, or in the concentration and/or tumor protective metabolism of glutathione/cysteine and other physiological cellular thiols; these antioxidants and enzymes are increased in concentration and/or activity, respectively, in response to the induction of intracellular oxidative stress which may be caused by exposure to cytotoxic chemotherapeutic agents in tumor cells. Additional information regarding certain mechanisms which may be involved in the biological activities of the Formula (I) compounds is disclosed in U.S. patent application Ser. No. 11/724,933, filed Mar. 16, 2007, the disclosure of which is hereby incorporated by reference in its entirety.
II. Physiological Cellular Thiols
Thiol groups are those which contain functional CH2—SH groups within conserved cysteinyl residues. It is these thiol-containing proteins which have been elucidated to play the primary role in redox-sensitive reactions. Their redox-sensing abilities are thought to occur by electron flow through the sulfhydryl side-chain. Thus, it is the unique properties afforded by the sulfur-based chemistry in protein cysteines (in some cases, possibly in conjunction with chelated central metal atoms) that is exploited by transcription factors which “switch” between an inactive and active state in response to elevated concentrations of ROS and/or RNS. It should be noted that the majority of cellular protein thiols are compartmentalized within highly reducing environments and are therefore “protected” from such oxidation. Hence, only proteins with accessible thiol moieties, and higher oxidation potentials are likely to be involved in redox-sensitive signaling mechanisms.
There are numerous naturally-occurring thiols and disulfides that are involved in oxidative metabolism. The most abundant biologically-occurring amino acid is cysteine, along with its disulfide form, cystine. Another important and highly abundant intracellular thiol is glutathione (GSH), which is a tripeptide comprised of γ-glutamate-cysteine-glycine. Thiols can also be formed in those amino acids which contain cysteine residues including, but not limited to, cystathionine, taurine, and homocysteine. Many oxidoreductases and transferases rely upon cysteine residues for their physiological catalytic functions. There are also a large number of low molecular weight cysteine-containing compounds, such a Co-enzyme A and glutathione, which are vital enzymes in maintaining oxidative/reductive homeostasis in cellular metabolism. These compounds may also be classified as non-protein sulfhydryls (NPSH).
Structural and biochemical data has also demonstrated that thiol-containing cysteine residues and the disulfide cystine, play a ubiquitous role in allowing proteins to respond to ROS. The redox-sensitivity of specific cysteine residues imparts specificity to ROS-mediated cellular signaling. By reacting with ROS, cysteine residues function as “detectors” of redox status; whereas the consequent chemical change in the oxidized cysteine can be converted into a protein conformational change, hence providing an activity or response.
Within biological systems, thiols undergo a reversible oxidation/reduction reaction, as illustrated below, which are often catalyzed by transition metals. These reactions can also involve free radicals (e.g., thioyl RS) as intermediates. In addition, proteins which possess SH/SS groups can interact with the reduced form of GSH in a thiol-disulfide exchange. Thiols and their disulfides are reversibly linked, via specific enzymes, to the oxidation and reduction of NADP and NADPH. This reversible oxidation/reduction reaction is shown in Table 1, below:
TABLE 1 
There is increasing experimental evidence that indicates that thiol-containing proteins are sensitive to thiol modification and oxidation when exposed to changes in the redox state. This sensing of the redox potential is thought to occur in a wide range of diverse signal transduction pathways. Moreover, these redox sensing proteins play roles in mediating cellular responses to changes in intracellular oxidative metabolism (e.g., increased cellular proliferation).
One of the primary enzymes involved in the synthesis of cellular thiols is cysteine synthase, which is widely distributed in human tissues, where it catalyzes the synthesis of cysteine from serine. The absorption of cystine and structurally-related amino acids (e.g., ornithine, arginine, and lysine) are mediated by a complex transporter system. The Xc transporter, as well as other enzymes, participate in these cellular uptake mechanisms. Once transported into the cell, cystine is rapidly reduced to cysteine, in an enzymatic reaction which utilizes reduced glutathione (GSH). In the extracellular environment, the concentrations of cystine are typically substantially higher than cysteine, and whereas the reverse is true in the intracellular environment.
III. Lung Cancer
Lung cancer is reported to be the leading cause of smoking- and cancer-related mortality in both sexes. The prevalence of lung cancer is second only to that of prostate cancer in men and breast cancer in women. In the United States, lung cancer was reported recently to surpass heart disease as the leading cause of smoking-related mortality. Most lung carcinomas are diagnosed at an advanced stage, conferring a poorer prognosis. Lung cancer is estimated to be the cause of 921,000 deaths each year worldwide, accounting for approximately 18% of all cancer-related deaths. Lung cancer is highly lethal, with a 5-year patient survival rate of only 14% being observed in the United States. An estimated 164,100 (i.e., 89,500 in men and 74,600 in women) new lung cancer cases will occur this year (2008) in the United States. See, e.g., National Cancer Institute-2008 Lung Cancer Estimates (www.Cancer.gov).
Lung cancer manifests with symptoms produced by the primary tumor, locoregional spread, metastatic disease, or ectopic hormone production. Approximately 7-10% of patients with lung cancer are asymptomatic and their cancers are diagnosed incidentally after a chest x-ray performed for other reasons. The symptoms produced by the primary tumor depend on its location (e.g., central, peripheral).
Of the symptoms produced by the primary tumor, central tumors are generally squamous cell carcinomas and produce symptoms or signs of cough, dyspnea, atelectasis, post-obstructive pneumonia, wheezing, and hemoptysis, and peripheral tumors are generally adenocarcinomas or large cell carcinomas and, in addition to causing cough and dyspnea, can cause symptoms or signs from pleural effusion and severe pain as a result of infiltration of parietal pleura and the chest wall. Symptoms due to locoregional spread can include: (i) superior vena cava obstruction; (ii) paralysis of the left recurrent laryngeal nerve and phrenic nerve palsy (causing hoarseness and paralysis of the diaphragm); (iii) pressure on the cervical sympathetic plexus (causing Horner syndrome); (iv) dysphagia resulting from esophageal compression; (v) pericardial effusion and cardiac tamponade; and (vi) superior sulcus apical primary tumors can cause compression of the brachial plexus roots as they exit the neural foramina, causing intense, radiating neuropathic pain in the ipsilateral upper extremity (e.g., Pancoast tumors). Lung cancer is associated with a variety of paraneoplastic syndromes: (i) most of such paraneoplastic syndromes are associated with small cell lung cancer; (ii) squamous cell carcinomas are more likely to be associated with hypercalcemia due to parathyroidlike hormone production; and (iii) clubbing and hypertrophic pulmonary osteoarthropathy and the Trousseau syndrome of hypercoagulability are caused more frequently by adenocarcinomas. Eaton-Lambert myasthenic syndrome is reported in association with small cell and non-small cell lung cancers. Paraneoplastic syndromes can pose debilitating problems in cancer patients and can complicate the medical management of such patients.
Non-small cell lung cancer (NSCLC) accounts for more than 80% of all primary lung cancer, and surgically resectable (with curative intent) cases account for less than 30%. Chemotherapy and radiotherapy are the mainstays of treatment in unresectable cases, but the median survival period is only 15-20 months and the 3-year survival rate is approximately 30-40% in stage IIIA and IIIB cases. The prognosis is even worse in stage IV patients with a median survival period of 8-10 months and a 1-year survival rate of less than 30%. At these advanced stages, the main therapeutic objectives are increasing the survival period and preserving the quality of life; these patients are not generally considered curable. It is important to consider the important concept of increasing the observed survival rate as a prerequisite for achieving a curative outcome in any therapeutic intervention that involves a defined patient population (e.g., non-small cell lung cancer patients) that is considered to be incurable. See, e.g., Cortes-Funes H., New Treatment Approaches for Lung Cancer and Impact on Survival. Semin. Oncol. 29:26-29 (2002); Fukuoka, M. and Saijoh, N., Practical medicine-Lung cancer, Nannkodo (2001). NSCLC is pathologically characterized further into adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and other less common forms. Clinically there are also important differences in NSCLC that can be observed in smokers and non-smokers.
A summary of clinical characteristics by histologic NSCLC subtype include:                Adenocarcinoma is the most frequent non-small cell lung cancer (NSCLC) in the United States, representing 35% to more than 50% of all lung cancers, usually occurring in a peripheral location within the lung and arising from bronchial mucosal glands. Adenocarcinoma is the most common histologic subtype, manifesting as a scar carcinoma. This is a subtype observed most commonly in persons who do not smoke, however, adenocarcinoma is also common in smokers. This type of NSCLC may also manifest as multifocal tumors in a bronchoalveolar form. Bronchoalveolar carcinoma is a distinct subtype of adenocarcinoma with the classic manifestation as an interstitial lung disease upon radiographic imaging. Bronchoalveolar carcinoma arises from type II pneumocytes and grows along alveolar septa. This subtype may manifest as a solitary peripheral nodule, multifocal disease, or a rapidly progressing pneumonic form. A characteristic finding in persons with advanced disease is voluminous watery sputum. Overexpression of thioredoxin and/or glutaredoxin has been noted in adenocarcinomas of the lung.        Squamous cell carcinoma accounts for approximately 25-30% of all lung cancers. The classic manifestation is a cavitary lesion in a proximal bronchus. This type is characterized histologically by the presence of keratin pearls and can be detected based on results from cytologic studies because it has a tendency to exfoliate. It is the type most often associated with hypercalcemia.        Large cell carcinoma accounts for approximately 10-15% of lung cancers, typically manifesting as a large peripheral mass upon radiographic imaging. Histologically, this type has sheets of highly atypical cells with focal necrosis, with no evidence of keratinization (typical of squamous cell carcinoma) or gland formation (typical of adenocarcinomas). Patients with large cell carcinoma are more likely to develop gynecomastia and galactorrhea as paraneoplastic syndromes.        
Various types of lung cancer have been shown to have an increased oxidative metabolism and/or increased concentrations of thioredoxin and/or glutaredoxin, and may further overexpress these in response to chemotherapy, thus resulting in tumor-mediated drug resistance to chemotherapy. Therefore, any tumors that possess the characteristics of an increased oxidative metabolism and/or increased concentration of thioredoxin and/or glutaredoxin are more amenable to the therapeutic benefits, including increased survival outcomes that would be mediated by an intervention from a composition or method of the present invention.
IV. Adenocarcinoma
Adenocarcinoma is a histopathological description and classification of cancers that originate primarily from glandular tissue. Glandular tissue comprises organs that synthesize a substance for release such mucin or hormones. Glands can be divided into two general groups: (i) endocrine glands—glands that secrete their product directly onto a surface rather than through a duct, often into the blood stream and (ii) exocrine glands—glands that secrete their products via a duct, often into cavities inside the body or its outer surface. Exocrine glands may be further differentiated into three categories: apocrine, holocrine, and merocrine. However, it should be noted that to be classified as adenocarcinoma, the cells do not necessarily need to be part of a gland, as long as they have secretory properties. Adenocarcinoma may be derived from various tissues including, but not limited to, breast, colon, lung, prostate, salivary gland, esophagus, stomach, liver, gall bladder and bile ducts, pancreas (99% of pancreatic cancers are ductal adenocarcinomas), cervix, vagina, ovary, and uterus, prostate, as well as unknown primary adenocarcinomas, which are not uncommon.
Adenocarcinoma is a neoplasm which frequently presents marked difficulty in differentiating from where and from which type of glandular tissue the tumor(s) arose. Thus, an adenocarcinoma identified in the lung may have had its origins (or may have metastasized) from an ovarian adenocarcinoma. Cancer for which a primary site cannot be found is called cancer of unknown primary, and adenocarcinomas of unknown primary are the most common type of unknown primary cancers. The primary site is identified in only approximately 10-20% of patients during their remaining life times and it frequently is not identified until post-mortem examination. It has been reported that approximately 60% of patients (i.e., over 50,000 patients per annum in the United States) who are diagnosed with carcinoma of unknown primary site suffer from adenocarcinoma.
A diagnosis of adenocarcinoma which is not further described (i.e., adenocarcinoma not otherwise specified; adenocarcinoma NOS) is often a preliminary diagnosis and can frequently be clarified with the use of immunohistochemistry or fluorescent in situ hybridization (FISH) (see, e.g., Dabbs, D. J. and Silverman, J. F., Immunohistochemical and Fluorescent in situ Hybridization Workup of Metastatic Carcinoma of Unknown Primary. Path. Case Rev. 6(4):146-153 (2005)), and/or various imaging methodologies including, but not limited to, computerized tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET).
Immunohistochemistry refers to the process of localizing proteins in cells of a tissue section exploiting the principle of antibodies binding specifically to antigens in biological tissues. Immunohistochemistry is also widely used in basic research to understand the distribution and localization of biomarkers in different parts of a tissue. Immunohistochemical staining is a widely used specialized technique in the diagnosis of cancer and the classification of neoplasms. The antibodies utilized may be either polyclonal or monoclonal in nature and may be directed against cell components or products which can include: (i) enzymes (e.g., prostatic acid phosphatase, neuron-specific enoenzymes); (ii) normal tissue components (e.g., keratin, neurofilaments); and (iii) hormones or hormone receptors (e.g., estrogen receptor, oncofetal antigens, S-100 proteins). It should be noted that specific molecular markers are characteristic of particular cancer types. For example, adenocarcinoma often gives positive immunohistochemical results for thyroid transcription factor-1 (TTF-1). Visualizing an antibody-antigen interaction can be accomplished in a number of ways. In the most common instance, an antibody is conjugated to an enzyme, such as peroxidase, that can catalyze a color-producing reaction, as with immunoperoxidase staining. Alternatively, the antibody can also be tagged to a fluorophore, such as FITC, rhodamine, Texas Red, or DyLight Fluor, as with immunofluorescence.
Fluorescent in situ hybridization (FISH) is a cytogenetic technique that can be used to detect and localize the presence or absence of specific DNA sequences on chromosomes. It utilizes fluorescent-tagged nucleic acid probes that bind to only those parts of the chromosome with which they show a high degree of nucleotide sequence complementarity. Fluorescence microscopy can be used to find out where the fluorescent probe bound to the chromosome.
Adenocarcinomas are quite common and arise in a variety of sites. Similar to NSCLC, it has also been shown that adenocarcinomas have an increased oxidative metabolism and/or increased concentrations of thioredoxin and/or glutaredoxin, and may further overexpress these in response to chemotherapy, resulting in tumor-mediated drug resistance to chemotherapy.
As set forth above, non-small cell lung carcinoma (NSCLC) and adenocarcinoma are highly prevalent forms of cancer and account for a large percentage of the deaths associated with cancer world-wide. Given the relatively refractory nature of NSCLC and adenocarcinoma to many forms of therapy, there remains a need for the development of compositions and treatment regimens that are both generally safe and effective for increasing the survival time of patients receiving chemotherapy, slowing the progression of their tumors, and/or stimulating or maintaining the beneficial physiological function of important bodily processes in normal (i.e., non-cancerous) cells and tissues. It has also been recognized that both NSCLC and adenocarcinomas have an increased oxidative metabolism and/or increased concentrations of thioredoxin and/or glutaredoxin, and may further overexpress these in response to chemotherapy, resulting in tumor-mediated drug resistance to chemotherapy. Therefore, any tumors that possess these characteristics are more amenable to the therapeutic benefits, including increased survival outcomes, which would be mediated by an intervention from a composition or method of the present invention. Recent, surprising and medically-important new finding and functions, based upon recent clinical trial results, have been observed involving the Formula (I) compounds set forth in the present invention. These observations have extremely important implications for the treatment of cancer and various other medical conditions.
In addition to the foregoing considerations regarding cancer, many patients, including cancer patients receiving chemotherapy, are also in need of: maintaining or stimulating hematological function; maintaining or stimulating erythropoietin function or synthesis; mitigating or preventing anemia; and maintaining or stimulating pluripotent, multipotent, and unipotent normal stem cell function or synthesis.